000
AXPZ20 KNHC 300923
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
922 UTC Thu Nov 30 2017

Tropical Weather Discussion for the eastern Pacific Ocean from
the Equator to 32N, east of 140W. The following information is
based on satellite imagery, weather observations, radar, and
meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: 1023 mb high pressure is
building north of the area over central Mexico, setting up a
tight pressure gradient across the isthmus of Tehuantepec
resulting in gap winds to gale force into the Gulf of
Tehuantepec through Sat morning, pulsing back again to gale Sat 
night. During this extended gale event, seas are forecast to peak
at 12-14 ft early this morning, with downstream seas of 8 ft and
higher reaching as far as 500 nm offshore. 

INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough axis extends from 09N83W TO 07N95W to 09N110W,
where it transitions to an intertropical convergence zone and
extending from 10N120W to beyond 07N140W. Scattered moderate
convection is observed within 60 nm south of the monsoon trough
in the Gulf of Panama. Scattered moderate convection also
observed within 240 nm north of the monsoon trough between 90W
and 95W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please see Special Feature section for detail concerning the 
gale warning in the Gulf of Tehuantepec.

Ridging extending across the region will maintain gentle to
moderate breezes across the entire area through early next week.
Long period northwest swell or 8 to 10 ft is propagating across 
the waters offshore of Baja California. A recent altimeter
satellite pass confirmed seas to as high as 10 ft off Cabo San
Lazaro in Baja California Sur. Reinforcing swell is moving south
of 30N, allowing combined seas to 12 ft off Baja California 
Norte tonight, reaching as far south as the Revillagigedo Islands
as 10 ft swell by early Sat. The swell will decay below 8 ft by 
late Mon. 

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...
  
Gulf of Papagayo: A modest pressure gradient between high 
pressure over the western Gulf of Mexico and lower pressure 
across the southwest Caribbean is producing fresh offshore gap 
winds across the Papagayo region. These winds will be enhanced 
with overnight drainage effects for the next few days, peaking 
near 25 kt during the late night through late morning hours. 
Seas downstream will build to 6 to 8 ft during the peak winds, 
with the winds and seas diminishing slightly each late afternoon 
through evening.

Light to gentle N to NE winds, and 4 to 5 ft seas are expected 
elsewhere through Sat N of the monsoon trough. Moderate 
southerly winds, and 4 to 6 ft seas, are forecast south of the 
monsoon trough. Northerly swell generated in the Gulf of 
Tehuantepec will reach the western part of forecast zone PMZ111 
(offshore waters of Guatemala and El Salvador) Thu through the 
end of the week.

REMAINDER OF THE AREA... 

A large area of NW swell producing seas of 8 to 15 ft across the
waters W of 120W will continue to propagate across the region, 
with the leading edge of 8 ft seas currently reaching from the 
southern Baja California peninsula to 00N140W, and will reach NW 
of a line from 16N111W to 00N135W to 00N140W Thu. A re- enforcing
pulse of NW swell currently moving through the far NW waters 
will spread SE and into the central waters through tonight. High
pressure north of the region will enhance a broad zone of NE to 
E winds across the tradewind belt W of 130W through Fri. Seas of 
8 to 12 ft are then expected to cover nearly the entire forecast 
waters S of 30N W of 110W into Sun, and will start to decay below
8 ft through early next week.

$$ 
Christensen